A ReadOnlyJavaBeanDoubleProperty provides an adapter between a regular read only Java Bean property of type double or Double and a JavaFX ReadOnlyDoubleProperty. It cannot be created directly, but a ReadOnlyJavaBeanDoublePropertyBuilder has to be used.
As a minimum, the Java Bean must implement a getter for the property. If the getter of an instance of this class is called, the property of the Java Bean is returned. If the Java Bean property is bound (i.e. it supports PropertyChangeListeners), this ReadOnlyJavaBeanDoubleProperty will be aware of changes in the Java Bean. Otherwise it can be notified about changes by calling fireValueChangedEvent().
Returns the current value of this ObservableDoubleValue.